Abstract

Background

The current standard first-line treatment for the majority of patients (pts) with extensive-stage small cell lung cancer (ES-SCLC) is platinum-based chemotherapy with etoposide. Despite initial response rates ranging from 50% to 70%, median survival remains

Trial design

IMpower133 is a randomized, Phase III, multicenter, double-blinded, placebo-controlled study evaluating the efficacy and safety of atezo + CE vs placebo + CE in treatment-naive pts with ES-SCLC. Pts will be enrolled regardless of PD-L1 expression status. Pts with untreated CNS metastases, autoimmune disease or prior anti-cancer therapy for ES-SCLC will be excluded. Eligible pts will be stratified by sex, ECOG PS and presence of brain metastases, and randomized 1:1 to treatment arms. The induction phase of the study will consist of four 21-day cycles of atezo (1200 mg IV) or placebo with CE (C AUC 5, day 1 + E 100 mg/m2, days 1-3) followed by maintenance atezo or placebo until PD per RECIST v1.1. Treatment can be continued until persistent radiographic PD or symptomatic deterioration. Investigator-assessed PFS per RECIST v1.1 and OS are the co-primary endpoints. Secondary endpoints include ORR, DOR, quality of life, safety/tolerability and pharmacokinetics. Approximately 400 pts will be enrolled globally.